Rack guide unit

Abstract

A rack guide unit includes a closure member, a rack guide, and an urging unit. The closure member is secured to an external opening end of an accommodation portion of a housing. The rack guide is accommodated in the accommodation portion so as to be movable in an advancing/withdrawing direction and supports the rack shaft so that the rack shaft is slidable in an axial direction. The urging unit is arranged between the closure member and the rack guide. The urging unit includes a stack of a plurality of coned disc springs urging the rack guide toward the rack shaft and arranged in an identical orientation, and an auxiliary coned disc spring that serves as a holding member holding the stack.

What is claimed is: 
     
       1. A rack guide unit comprising:
 a housing having an accommodation portion through which a rack shaft that is meshed with a pinion shaft passes; 
 a closure member secured to an external opening end that is provided on the opposite side of the accommodation portion from the rack shaft; 
 a rack guide that is accommodated in the accommodation portion so as to be movable in an advancing/withdrawing direction toward the rack shaft or the closure member, and that supports the rack shaft so that the rack shaft is slidable in an axial direction of the rack shaft; and 
 an urging unit that includes a stack of a plurality of coned disc springs urging the rack guide toward the rack shaft and arranged in an identical orientation and a holding member holding the stack, and that is arranged between the closure member and the rack guide, wherein
 the rack guide unit includes an auxiliary coned disc spring that serves as the holding member, the auxiliary coned disc spring arranged in series with the stack and tilted in a free state toward a side opposite a side toward which the stack is tilted, and 
 the auxiliary coned disc spring includes an annular auxiliary coned-disc-spring main body, and a plurality of holding hooks extending from a radially inner portion or a radially outer portion of the auxiliary coned-disc-spring main body and engaged with a radially inner portion or a radially outer portion of the stack. 
 
 
     
     
       2. A rack guide unit comprising:
 a housing having an accommodation portion through which a rack shaft that is meshed with a pinion shaft passes; 
 a closure member secured to an external opening end that is provided on the opposite side of the accommodation portion from the rack shaft; 
 a rack guide that is accommodated in the accommodation portion so as to be movable in an advancing/withdrawing direction toward the rack shaft or the closure member, and that supports the rack shaft so that the rack shaft is slidable in an axial direction of the rack shaft; and 
 an urging unit that includes a stack of a plurality of coned disc springs urging the rack guide toward the rack shaft and arranged in an identical orientation and a holding member holding the stack, and that is arranged between the closure member and the rack guide, wherein
 the rack guide unit includes an auxiliary coned disc spring that is arranged in series with the stack and tilted in a free state toward a side opposite a side toward which the stack is tilted; and 
 the holding member includes a holding member main body interposed between the stack and the auxiliary coned disc spring, a plurality of first holding hooks extending from the holding member main body and engaged with a radially inner portion or a radially outer portion of the stack, and a plurality of second holding hooks extending from the holding member main body and engaged with a radially inner portion or a radially outer portion of the auxiliary coned disc spring. 
 
 
     
     
       3. The rack guide unit according to  claim 1 , wherein the auxiliary coned disc spring is initially set in a close-contact state. 
     
     
       4. The rack guide unit according to  claim 1 , wherein the holding member includes an aligning projection that is engaged with a recessed portion formed in either one of opposite faces of the rack guide and the closure member so that the stack is aligned with the rack guide or the closure member.